Apparatus for testing voltage regulators



Filed Nov. 24, 1944 2 Sheets- Sheet 1 June 7, 1949. L. R. NIXON2,472,545

APPARATUS FOR TESTING VOLTAGE REGULATORS June 7, 19 49.-

APPARATUS FOR TESTING V6LTAGE REGULATORS Filed Nov. 24, 1944 2Sheets-Sheet 2 Patented June 7, 1949 land; assign'orto J2; I StoneCompany Limited; Deptford; Englandha British joint-stock com-Application-November 24, reM', s'eria1 -No; realise InGr'e'at BritainMarch is; 1944 This invention relates to improvements con nected withapparatus for testing electric rogu lators of= the carbon pile'type'andhas-for its'obje'ct to provide" a simple and reliable testing means foruse in: re-setting' that class: of regulator wherein compression of? thepile is increased by electro magnetic action; Ins thet'usual: carbonpile regulator; the pile is normally heldeimcompression by a; controlspring and the 'electro magnet i's so arrangedin relation to the pileand spring that ex-ce'ss' current applied causes: it -to overcome the"pull of the spring"- and thereby to relievethe" compression of the"pile? For such regulators; pile adjusters" and indicators have beenprovided,- whereby; during: serviceth'e pilecould be renewed 'orrepaired 'and the ri' readily adjusted-so as to=receive the original correct set ting given to it on the test' ben'ch.

In some circumstances, it becomes nec'essa1'3" to employare'gnlatorwherein thepile is normally unden'minimum compression and isadditionally compressed against the actiomof a control spr ing as-thenergization of the electro-m'ag'n'et iii-- creases, and thisis thecondition obtaining iri' the case of scme pilot regulators. lri suchregu lators ma'gnet torque=spring torqne-l-pile reac: tion' torque:

According;- to: this inventionz in a regulator wherein pilecompre's'sioniis increased by electrd magnetic action;there-areprdvidetl -testing m'eans comprising in combination springmeans'icf predetermined 1 value adapted for applying commas-- sion: tothe pile when the regulator nragneti is de -energized and: indicatormeans adapted for indicating the setting ofthepile 'when underrthecompressive influence of the said spring: means; An indicatorsuitable-for this-purpose is disclosed in United States patent toChilton et' a1. N02 2374,41, dated April 24; 1945.

Thespring means may be applied so as to oppose' and: overcome thecontrol springa whicli' is normally operative in the direction" ofpiledecompression Or; the control spring may be: readily.detachableordisengageable :so as-to per'-- mit theforce of the spring:means of known value? 45 4 Cla1ms. (ClL-73--1),

pile regulator; in'which the'magne-t operates-to compress the pile;may-be use'diriconnection with' the field circuit of all Cnmo't'o'r.

Figure: 3 is: a: side elevation and Figure- 4' is a: plan view of aknown'kind of carbon-pile regulator embodying the present improvements.

Figure 5 isasectional 1 view' to a largerscale of a press buttontesting: device seen in Figures 3" and 4.

Figure 6: is a: fragmental side" elevation illustrating a modification;and

Figure '7" is" similar to a portion of Figure 6 bill?- showing a furthermodification;

Refer-ring toFigure"1,--P'indlca.t'es the-pile of a; regulator forregulating the output voltage (DV- of a circuit Iv being the'inputvoltage. In this regulator; the magnet coilC which-'is-affected by: theinput voltage becomes operativefor dje-com' pressingthepileP in theusual manner. The coil 6, however, isinseries with a pile P of a;pilot-regulator, the'collfi oi the latter being con-- n'ected across theoutput voltage'in series with'a variable resistance The coil C of the?pilot regulator operates'in areverse mannercompared with the coil C-iorit becomes effective when energiZE'dfOl variably compressing the pile PInsuch an installation, th'e main regulator C, P may be a comparativelycrude 'piece of apparatus: and theaccuracyrof the regulated voltage iscontrolled completely 'by the pilot regulator C P Referring: toFigure-1A: is the armature and F i's-thefield v'vinding:ofa D; C. motor,the carbon; pileP -ef a regulator beingins'erted in the field windingcircuit; The pileP is' var'iably compressed by am'ag-net ener'gized'by'a coil G and operating against a. spring which tends constan'tly toie=compressthe pile-P The coil c of this regulator may be ex'cited byatachometer generator G mechanically dr'ivenfrom the motor andsensitive-to-spee'd changes. With tliis" ar rangement; any: increase ofspeed over tlie"required value=causes the: coil C to produce'addb:tional: compression of the pile P thereby in creasin the motor fieldstrerigth and restoring the: correctspeed value:

The foregoing are-two examples of circuitsin which an-electric regulatorembodying'the-pres'entf' improvements may be: employed;

Referring to'Figures: 3 and 4-; a is 1 the framing;

'of an electric regulatorof known kind' comprising amagnetb' andacarbonpile c.v The armaturedis sepiece o f-iron oi U-section -as seen-end on=pre-"-- senting-two blades for attra'ctioninto polar gapsof the magnetb inkncwrn manner. The arma ture d'is straddled and fixed on the stem eof a Y-shaped casting serving as carrier, the two divergent branches ofwhich are marked e and e respectively. This carrier is supportedpivotally in known manner and substantially frictionlessly by means ofhorizontal and vertical spring blades f and g, Figure 3, each havin oneend affixed to the frame a and the other end affixed to suitably shapedprojections formed on the branches e e of the carrier (cf. also Figure6) is thus provided at the intersection a: between the blades 1 and g inknown manner. The armature piece 01 is thus carried at the end of a longlever arm extending downwardly beneath the pivotal axis a: in Figure 3.As regards the short arm of the lever provided by the branches 6 eextending above the pivotal axis 3: these are connected by flexibleconnectors such as short steel tapes h, Figures 3 and 4, with a presserring 7' which is operative against the movable end of the pile c. Theopposite end of the pile c is abutted against a screw threaded abutmentis which is adjustable in a plate a of the framing. The branch e of thecarrier is slotted at its extremity and the slotted end is engaged by ascrew stud I, Figure 4, connected with one end of a spring the other endof the spring bein connected with a screw n which is adjustably fixed bynuts n in a bimetallic strip afiixed to the framing a.

The regulator above described works in the following manner: With themagnet b de-energized, the spring 112 acting on the short arm of theaforesaid lever turns the carrier 9, e e counter-clockwise about thepivot axis x, thereby withdrawing the armature d from the polar gaps ofthe magnet b and relaxing the connectors h so that the pile c isdecompressed. The slack state of the connectors h, in this condition ofthe parts is to be seen in Figure 3. When the magnet b is energizedsufficiently the attraction of the armature d, which is on the long armof the lever, overcomes the effort of the spring acting upon the shortarm and the carrier e, 6 e is thus turned clockwise about the pivotalaxis x. The result is that the connectors h are put under tension andthe presser ring 7 is pulled more or less strongly against the movableend of the pile c to put the latter under variable compression.

The present improvements, according to one example, provide in aregulator of the kind above described and in conjunction with the longlever arm of the carrier e, e 6 a press button device indicatedgenerally by the letter p in Figures 3 and 4 and shown in detail inFigure 5. Referring to Figure 5, the press-button device p comprises acylindrical casing 21 which is slidable in a socket q fixedly mounted inthe frame plate a The stem 1" of a plunger 1 protrudes through a hole inone end cover of the casing p and is normally pressed outwardly to thefull extent shown by a calibrated spring s operating between the plungerr and an abutment ring t screwed into the other end of the casing. Thisend of the casin is fitted with a perforated cap it which is fastened tothe casing p by tags p on the latter which are passed through slots inthe cap u and bent over as shown. A light spring 1; constantly pressesthe casing p rightwardly and upwardly in Figure 5 and for this purposeit reacts between one end of the socket q and the cap u, the latterbeing formed with a skirt u which partly encloses the spring 12 andwhich also serves as a stop when the casing 72 is pressed leftwards anddownwards as hereinafter explained. The rightward upward movement of thecasing p under the influence of the spring 1) is limited by a stopflange p on the casing coming against the inner end of the socket q asshown.

Normally, the press button devise occupies the position seen in Figure3, wherein the stem 1 of its plunger is seen to be out of contact with ashaped part 20 on the pivotal carrier e, e e.

A pivotal axis When a test or re-setting operation is to be performed onthe regulator, the magnet b is deenergized so that the parts may occupythe position seen in Figure 3. The casing p of the press button is thenpressed inwards against the action of the spring 1) until arrested bythe skirt u coming against the outer end of the socket q. This pressingin of the button first brings the stem 1' of the plunger against theshaped part w which presents an abutment surface perpendicular to theaxis of the stem r. Thereafter, and during the pressing in of the casing10 to its full limit, the internal calibrated spring 3 becomescompressed to a predetermined degree. The spring s is calibrated so thatwhen compressed in the manner described it overcomes the pull of themain control spring m acting on the short lever arm and applies apredetermined compressive force to the pile c. To indicate the effect ofthe press button operation an indicator device is required. This may beprovided in the following manner: On the branch 6 of the carrier thereis fixedly mounted a known counterbalance weight 1 Figures 3 and 4, andthis weight serves conveniently for the mounting of a pointer in theform of a light finger z of sheet metal bearing an arrow head 2 Figure3. Opposite this pointer there is a curved extension a of a frame plateand such extension is provided with a scale or with a single mark I asshown. Now, when the press button is pressed in as above described, itcauses the carrier 6, e e to turn about the axis at, as explained.Consequently, the weight y and pointer a move with the carrier, thepointer 2 moving in indicative relation with the extension a If the pilec r is in correct adjustment, the arrow 2 on the pointer will come intoalignment with the mark I on the extension a or opposite a given mark ona scale if one is provided. If, on the other hand, the pile is inincorrect adjustment, the arrow 2 will show a deviation from the mark I.The setting can then be adjusted by operating the abutment screw iswhich adjusts the pile bodily one way or the other, until the arrow 2registers accurately with the mark I when it will be known that thesetting of the pile has been corrected.

According to a modification illustrated in Figure 6, the main controlspring m of the regulator is detachably connected with the short leverarm if the carrier 6, e for example by fitting it at the appropriate endwith a knife edge bearing device 2 which is disengageable from aV-seating 3 on the branch e**. The long arm of the lever has connectedwith it one end of a relatively light spring 4 having its other endconnected with the frame part a. The spring 4 always tends to assist themagnet b as will be understood from Figure 6 which shows the armaturepiece d attracted into,

the polar gaps, the magnetic attraction having overcome the main controlspring m in order to put the pile under compression as hereinbefore,explained. With this arrangement, when the regulator is to be tested orre-set, the magnet b is ole-energized and the knife edge device 2 isdisengaged from the V-seating 3. The carrier or two armed lever e, e isnow subjected only to the forces of pile reaction and the effort of therelatively light spring 4 tending to compress the pile. The spring 4 iscarefully calibrated before being fitted so that a predeterminedcompression of a correctly set pile will be attained under the action ofthe spring 4. If the pile is in correct adjustment this will be shown byindicator means such as that hereinbefore described and if the pile isin incorrect adjustment, it must be adjusted in the .manner describeduntil the indicator shows that a correct setting has been achieved.

According to the further modification illustrated in Figure 7, thespring 4 is detachable from the stem e of the carrier so that it doesnot normally assist the magnet 12' but remains idle and relaxed. InFigure 7 the parts are shown in the position occupied when the magnet bis de-energized. A test is made when the magnet is de-energized bydetaching the main control spring 112 from the carrier, as explainedwith reference to Figure 6, and attaching the spring 4 to the stem e ofthe carrier. A testing operation with the arrangement in Figure 7 thenproceeds in precisely the same manner as described with reference toFigure 6.

I claim:

1. In a testing device for electric regulators of the carbon pile typewherein compression of the pile is effected by a magnet operatingagainst a main spring; a casing, a spring-loaded plunger enclosed insaid casing, a frame for the regulator having a fixed slideway in whichsaid casing is guidingly mounted and depressible therein for bringingsaid plunger into resilient engagement with a movable part of theregulator in opposition to said main spring, and stop means limiting thedepression of said casing and the ultimate spring load on said plunger.

2. In a testing device for electric regulators as claimed in claim 1, areturn spring normally operative for supporting said casing in awithdrawn and inoperative position, and stop means for limiting thereturn movement of said casing under the action of said return spring.

3. In a testing device for electric regulators of the carbon pile typewherein compression of the pile is effected by a magnet operatingagainst a main spring; said testin device comprising a calibratedspring, a casing enclosing said calibrated spring, a plunger slidableinwardly of said casing against the action of said calibrated spring,stop means on said casing for arresting movement of said plungeroutwardly of said casing, a framing for the regulator, guide meansfixedly disposed in the framing of the regulator and slidably supportingsaid casin whereby the latter can be moved towards and from a movablepart of the regulator, a rod on said plunger normally projecting fromsaid casing for resilient engagement with a movable part of theregulator during forward sliding movement of said casing and stop meanslimiting said forward sliding movement.

4. In a testing device for electric regulators as claimed in claim 3, areturn spring normally operative on said casing for pressing the latterback in said guide means, and a stop adapted for limiting returnmovement of said casing under the action of said return spring.

LESLIE REGINALD NIXON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,600,176 Humphrey Sept. 14, 19261,825,491 Walters Sept. 29, 1931 1,842,323 Gluzek Jan. 19, 19321,857,149 Grob May 10, 1932 1,946,774 Wilms Feb. 13, 1934 2,374,417Chilton et al Apr. 24, 1945

